BBC bosses blamed the Yorkshire accent when they were hit with a slew of complaints about actors mumbling on police drama Happy Valley earlier this year.

But now the show’s writer has said it is not regional accents but new high-tech TVs that spoil the sound quality.

Sally Wainwright, whose new drama Walk Invisible about the Bronte sisters airs next week said TV bosses are now “hyper aware” of the sound and that it is “perfect” when it leaves the editing suite.

Defending the production quality of her new show set in 1840s on the cobbled streets of Haworth, West Yorkshire, Ms Wainwright said expensive flat screen TVs can be to blame for some sound distortion, particularly if they are set against a wall.